PHENOTYPIC VARIATION IN HEREDITARY BREAST-CANCER - CANCER CONTROL IMPLICATIONS

Objective: To study hereditary breast cancer pedigrees as models for the elucidation of the natural history of the disease, including early onset; bilaterality; and tumor associations in the heterogeneous variants to aid in its diagnosis and in targeting surveillance and treatment strategies. Setting: Oncology clinic and hereditary cancer institute. Patients and Other Participants: Physician- or self-referred probands. Interventions: None. Main Outcome Measure: Greater understanding of the diagnosis, surveillance, and treatment of hereditary breast cancer. Results: Eighteen pedigrees displayed the phenotypic variation of breast cancer's natural history, obligate gene carriers, and patterns of tumor combinations consonant with genetic heterogeneity. Conclusion: Hereditary breast cancer is an important public health problem accounting for about 9% of breast cancer cases. The recent identification of a molecular basis for the identification of a subset of hereditary breast cancer, and thereby the likelihood of the sequencing and cloning of the susceptibility gene(s), will enable targeting of surveillance and treatment measures toward patients at an inordinately high risk of developing cancer. Central to this entire process will be the identification of families with hereditary breast cancer.